jsonchema bump to v4 (2020-12 draft) breaks bma.blockchain.difficulties

Problem

Since jsonschema bump from v3 to v4, at least bma.blockchain.difficulties throws the error in this post.

Error

>>> from duniterpy.api import bma
>>> from duniterpy.api.client import Client
>>> c = Client("BMAS g1.duniter.org 443")
>>> c(bma.blockchain.difficulties)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/work/u23a14/ML/duniterpy/duniterpy/api/client.py", line 442, in __call__
    return _function(self, *args, **kwargs)
  File "/work/u23a14/ML/duniterpy/duniterpy/api/bma/blockchain.py", line 330, in difficulties
    return client.get(f"{MODULE}/difficulties", schema=DIFFICULTIES_SCHEMA)
  File "/work/u23a14/ML/duniterpy/duniterpy/api/client.py", line 359, in get
    return client.request_url(
  File "/work/u23a14/ML/duniterpy/duniterpy/api/client.py", line 274, in request_url
    parse_response(content, schema)
  File "/work/u23a14/ML/duniterpy/duniterpy/api/client.py", line 89, in parse_response
    jsonschema.validate(data, schema)
  File "/home/u23a14/.cache/pypoetry/virtualenvs/duniterpy-3m7gpsy_-py3.10/lib/python3.10/site-packages/jsonschema/validators.py", line 1117, in validate
    cls.check_schema(schema)
  File "/home/u23a14/.cache/pypoetry/virtualenvs/duniterpy-3m7gpsy_-py3.10/lib/python3.10/site-packages/jsonschema/validators.py", line 231, in check_schema
    raise exceptions.SchemaError.create_from(error)
jsonschema.exceptions.SchemaError: [{'type': 'object', 'properties': {'uid': {'type': 'string'}, 'level': {'type': 'number'}}, 'required': ['uid', 'level']}] is not of type 'object', 'boolean'

Failed validating 'type' in metaschema['allOf'][1]['properties']['properties']['additionalProperties']['$dynamicRef']['allOf'][1]['properties']['items']['$dynamicRef']['allOf'][0]:
    {'$defs': {'anchorString': {'pattern': '^[A-Za-z_][-A-Za-z0-9._]*$',
                                'type': 'string'},
               'uriReferenceString': {'format': 'uri-reference',
                                      'type': 'string'},
               'uriString': {'format': 'uri', 'type': 'string'}},
     '$dynamicAnchor': 'meta',
     '$id': 'https://json-schema.org/draft/2020-12/meta/core',
     '$schema': 'https://json-schema.org/draft/2020-12/schema',
     '$vocabulary': {'https://json-schema.org/draft/2020-12/vocab/core': True},
     'properties': {'$anchor': {'$ref': '#/$defs/anchorString'},
                    '$comment': {'type': 'string'},
                    '$defs': {'additionalProperties': {'$dynamicRef': '#meta'},
                              'type': 'object'},
                    '$dynamicAnchor': {'$ref': '#/$defs/anchorString'},
                    '$dynamicRef': {'$ref': '#/$defs/uriReferenceString'},
                    '$id': {'$comment': 'Non-empty fragments not allowed.',
                            '$ref': '#/$defs/uriReferenceString',
                            'pattern': '^[^#]*#?$'},
                    '$ref': {'$ref': '#/$defs/uriReferenceString'},
                    '$schema': {'$ref': '#/$defs/uriString'},
                    '$vocabulary': {'additionalProperties': {'type': 'boolean'},
                                    'propertyNames': {'$ref': '#/$defs/uriString'},
                                    'type': 'object'}},
     'title': 'Core vocabulary meta-schema',
     'type': ['object', 'boolean']}

On schema['properties']['levels']['items']:
    [{'properties': {'level': {'type': 'number'},
                     'uid': {'type': 'string'}},
      'required': ['uid', 'level'],
      'type': 'object'}]

JSON Drafts

From what I understood, v4 introduced 2020-12 and 2019-09 drafts and therefore the last one supported becomes default.

These drafts are JSON specifications for jsonschema schemas.

BMA

I quickly checked the other bma GET requests, and they seem to work. We don’t have (integration) tests checking that the GET requests are still working.

bma.blockchain.difficulties does not support 2020-12 draft, but supports previous ones.

This seems to be only affecting bma.blockchain.DIFFICULTIES_SCHEMA since it’s the only one declaring "items": [] items with a list. I would fix this one by using prefixItems as stated in this ticket.

Solutions

We have these choices:

• switch back to jsonschema v3.2.0, but, I would prefer the latter to keep the latest jsonschema version
• In DIFFICULTIES_SCHEMA:
  • set "$schema": jsonschema.Draft7Validator.META_SCHEMA["$id"],
  • remove the list [] wrapping, not sure if this is correct
  • set prefixItems

References

• https://json-schema.org/draft/2020-12/release-notes.html#changes-to-items-and-additionalitems
• https://python-jsonschema.readthedocs.io/en/stable/faq/#my-schema-specifies-format-validation-why-do-invalid-instances-seem-valid